Glaserite

Potassium sulfate

Arcanite
Names
Other names Potassium sulphate
Identifiers
CAS Number	7778-80-5 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:32036 Y
ChemSpider	22915 Y
ECHA InfoCard	100.029.013
E number	E515 (acidity regulators, ...)
KEGG	D01726 Y
PubChem CID	24507
RTECS number	TT5900000
UNII	1K573LC5TV Y
InChI InChI=1S/2K.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 Y Key: OTYBMLCTZGSZBG-UHFFFAOYSA-L Y InChI=1/2K.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 Key: OTYBMLCTZGSZBG-NUQVWONBAU
SMILES [K+].[K+].[O-]S([O-])(=O)=O
Properties
Chemical formula	K2SO4
Molar mass	174.259 g/mol
Appearance	White solid
Odor	odorless
Density	2.66 g/cm3
Melting point	1,069 °C (1,956 °F; 1,342 K)
Boiling point	1,689 °C (3,072 °F; 1,962 K)
Solubility in water	111 g/L (20 °C) 120 g/L (25 °C) 240 g/L (100 °C)
Solubility	slightly soluble in glycerol insoluble in acetone, alcohol, CS2
Magnetic susceptibility (χ)	−67.0·10−6 cm3/mol
Refractive index (nD)	1.495
Structure
Crystal structure	orthorhombic
Hazards
Main hazards	Irritant
Safety data sheet	External MSDS
R-phrases (outdated)	R22
S-phrases (outdated)	S36
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	6600 mg/kg (oral, rat)
Related compounds
Other anions	Potassium selenate Potassium tellurate
Other cations	Lithium sulfate Sodium sulfate Rubidium sulfate Caesium sulfate
Related compounds	Potassium hydrogen sulfate Potassium sulfite Potassium bisulfite Potassium persulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Potassium sulfate (K₂SO₄) (in British English potassium sulphate, also called sulphate of potash, arcanite, or archaically known as potash of sulfur) is a non-flammable white crystalline salt which is soluble in water. The chemical compound is commonly used in fertilizers, providing both potassium and sulfur.

When potassium sulfate is heated in water and subjected to swirling in a beaker, the crystals form a multi-arm spiral structure when allowed to settle. Potassium sulfate could be used to study spiral structures in the laboratory.

Potassium sulfate (K₂SO₄) has been known since early in the 14th century, and it was studied by Glauber, Boyle, and Tachenius. In the 17th century, it was named arcanuni or sal duplicatum, as it was a combination of an acid salt with an alkaline salt. It was also known as vitriolic tartar and Glaser's salt or sal polychrestum Glaseri after the pharmaceutical chemist Christopher Glaser who prepared it and used medicinally.

The mineral form of potassium sulfate, arcanite, is relatively rare. Natural resources of potassium sulfate are minerals abundant in the Stassfurt salt. These are cocrystallizations of potassium sulfate and sulfates of magnesium calcium and sodium.

Relevant minerals are:

The potassium sulfate can be separated from some of these minerals, like kainite, because the corresponding salt is less soluble in water.

Kieserite, MgSO₄·H₂O, can be combined with a solution of potassium chloride to produce potassium sulfate.